The present invention relates to field of carpentry accessories, and particularly to techniques for guiding a power saw to cut wood, and more particularly to a power saw guide used in combination with a power saw to cut off an orthogonal length of wooden plank.
When working with wood planking, there is a need to cut the planks to length at a right angle. There are many ways of cutting the plank such as a table saw or radial arm saw. These types of saws are sometimes too large and expensive for the average carpenter to carry to the job site. The typical carpenter uses a hand held circular or power saw when cutting a plank to length.
There are a number of accessories that can assist the carpenter in establishing right angles, miter cuts, space parallel cuts and so forth. For the carpenter to use an accessory, it must be simple, lightweight, durable and compact to be accepted by the trade since the tradesman can already do anything he needs to do with the tools that he has. For the carpenter or tradesman to add a new tool or replace an existing tool with the new tool, the new tool must successfully solve one or more small inconveniences from the job without adding pounds or cubic inches to the tool mass.
One such small inconvenience arises when the carpenter needs to cut off an orthogonal length of a plank. Traditionally, the way this is done is by laying a flat carpenter's square on the plank with one leg along the length of the plank and the other leg laying across the plank. Next the carpenter makes a transverse pencil line across the plank the whole run of the cutoff path. Then a saw, usually a hand-held circular saw used extensively by framing carpenters and the like, is used to follow the line across the plank.
The line is often difficult to follow as it may not have been well lit in the first place, and continued sawdust accumulation along the cut line, and vibration, may obscure the pencil line. The saw blade safety cover also obstructs the cut line, making it difficult to see either the pencil line or the blade at its intersection with the plank, and thus it is hard to be sure the blade path is true to the line. This results in undercuts, overcuts, and angled cuts that were suppose to be orthogonal. On outdoor jobs which rely on sunshine for light, as dusk approaches the visibility of the pencil line becomes more difficult to see. During the cutting of the plank it also becomes increasingly difficult to insure the alignment of the rotating blade and the pencil mark in the flurry of sawdust under the spring-loaded blade guard.
Because right angularity is built into the carpenter's saw, and the distance between the sole plate of the saw and the plane of the blade is constant, one would think there would be a more efficient way of making such saw cuts, and in fact the prior art has developed several devices which are used to establish the angle automatically and enable the saw to be merely moved across the fence or the like to make the cut. Typically these devices may be heavy and stationary, or complicated by the addition of a number of other functions.
In view of the above, it is evident that what is needed is a simple lightweight and durable device enabling a perpendicular saw cut to be accurately made on a wooden plank without visual reference to a pencil line drawn on the plank during the saw cut.